Humminbird SmartCast RF45 Advance Remote Sonar Sensor (Discontinued by Manufacturer) Gives you a better performance from your SmartCast RF15, RF25, and RF35 fish finder Greater depth capability, and longer in-water usage time than original RSS Programmable two-channel operation so you can fish with a buddy without crossing signals Flashing, internal light that you can switch on or off for night fishing For use in US and Canada only, and backed by one-year limited warranty